Heating system control apparatus



Jan. 22, 1 52 v. D. WISSMILLER ET AL 2,583,524

HEATING SYSTEM CONTROL APPARATUS 3 Sheets-Sheet 1 Filed Sept. 19, 1946 (Ittomeg Jan. 22, 1952 v. D. WISSMILLER ET AL 2,5 3,

HEATING SYSTEM CONTROL APPARATUS 3 Sheets-Sheet 2 Filed Sept. 19, 1946 Jan. 22, 1952 v. D. WISSMILLER ET AL 2,583,524

HEATING SYSTEM CONTROL APPARATUS Filed Sept. 19, 1946 3 Sheets-Sheet 3 Gltorneg Patented Jan. 22, 1952 UNITED STATES PATENT OFFICE HEATING SYSTEM CONTROL APPARATUS Vernon D. Wissmiller, Chicago, Ill., and Robert A, Beveridge, Minneapolis, Minn., assignors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a. corporation of Delaware Application September 19, 1946, Serial No. 698,014

6 Claims. 1

The present invention relates to an improved air-conditioning and heating system especially adapted for railway cars, residences and the like.

It is well known that controlling the temperature of a space to a fixed value does not necessarily result in a uniform feeling of comfort to an occupant of the space as outside temperatures vary. For instance, a particular tempera ture value for the spacein mild weather may seem too high for comfort, whereas, during very cold weather, the same temperature value may seem too low. It appears that one of the principal factors responsible for this condition is the temperature of the wall surfaces surrounding said space. Previous attempts to solve the problem by panel heating systems or by compensated temperature control systems have been only partially satisfactory.

The problem of maintaining uniform conditions of comfort is particularly troublesome in railway cars because of the considerable variation in the temperature and sun conditions affecting said cars. Changes in their direction of travel, speed of travel, changes in sun condition due to tunnels, deep ravines and the like, and other changes affecting the heating load, all have an appreciable effect on the maintenance of comfort within the cars. In addition to these factors, the problem is further complicated by the seating arrangements wherein some of the people sit much closer to the outer walls than other people and hence are more affected by wall temperature conditions.

It is therefore a principal object of this invention to provide a heating system and means for controlling the same for maintaining uniform conditions of comfort under widely varying conditions.

It is also an object to provide a heating system and control means therefor for a walled space wherein the effects of varying air motion on the outer walls and variations in sun etlects are made factors in the control of the said heating system.

It is a further object to provide means for controlling the temperature of a space wherein means are provided for controlling the temperature of at least a portion of the walls of said space and other means are provided for satisfying the major portion of the temperature changing demands of the said space.

It is an additional object to provide means for controlling temperature in a space comprising radiant temperature changing means for at least a portion of the walls of said space and to provide a circulating tempered medium having sufllcient temperature changing ability to meet the principal portion of the demand of the said space.

It is also an object to provide means for controlling the temperature of a space wherein the temperature of a fluid medium circulating through radiant temperature changing means in said space is inversely varied relative to outdoor temperature and wherein the temperature changing effect of a forced air temperature changing apparatus for said space is controlled in response to the temperature of said space.

It is a somewhat similar object to provide means for controlling the temperature of a space wherein the temperature of a fluid medium circulating through radiant temperature changing means in said space is inversely varied relative to the temperature of the outer wall of said space and wherein other temperature changing means carries the major portion of the temperature changing load.

It is a further object to provide a temperature changing system wherein one portion of the system has a relatively large thermal capacity but is capable of satisfying a relatively small. portion of the temperature changing demands whereas the other portion of the system which is capable of satisfying the most of the temperature changing demand is characterized by a relatively low thermal capacity.

It is an additional object to provide a heating system for a railway car wherein floor heat means extending along each side of the car are individually controlled so that the temperature of each of said floor heat means is varied inversely with the outer wall or outside air temperature on the respective side of the car and wherein the major portion of the heat needed is supplied by the overhead portion of the system.

It is a further object to provide floor heat means for a railway car in which a suitable liquid is circulated through a closed loop heat exchanger, the liquid being heated by steam supplied to conduit means in heat exchange relation with said liquid, the steam supply being adjusted to maintain the liquid at a temperature inversely variable with outdoor or outer wall temperature.

It is also an object to provide floor heat means for a railway car in which a closed loop heat exchanger is arranged with the principal portions of the loop adjacent and extending horizontally and which contains a suitable liquid positively circulated by pump means and which liquid is heated by a steam supplied conduit in heat exchange relation with said liquid.

It is a further object to provide floor heat like, not shown,

liquid is varied inversely with the outdoor tem-' perature.

It is an additional object to control heat radiating means in a railway car in a manner to compensate for changes in heat load due to variations in the speed of travel of the car.

It is also an object to individually control heat radiating means in a railway car in a manner to compensate for sun eflects on the respective sides of the car.

These and other objects will become clear upon a study or" the following specification and drawing wherein:

Figural is a schematic illustration of the present apparatus installed in a railway car.

Figure 2 is an enlarged elevation view with parts in section showing a floor heat means.

Figure 3 is a sectional elevation of a skin temperature responsive device taken on the line 3-3 in Figure 1.

Figure 4 is a schematic wiring diagram showing how the apparatus of Figure 1 is connected.

Figure 5 is a modification showing schematically the present system applied to a residential building.

Referring to Figure l, where the present apparatus is shown installed in a railway car l0, it is noted that the apparatus includes an overhead heating system indicated generally as H, and floor heat means l2 and I3. Floor heat means 12 and I3 extend substantially the length of the car, or at least the space, and are arranged adjacent the side walls of the car and near the floor, as shown.

As best shown in Figure 2, floor heat means l2 includes horizontal conduit means [4 and connected at their ends to form a closed loop.

A suitable heat exchange liquid [6, such as a mixture of water and ethylene glycol, is circulated through the said loop by a conventional motor driven circulator 11, preferably arranged in conduit l4. Any suitable expansion means, such as a closed tank, expansible bellows, or the may be provided for each of the floor heat means to accommodate the expansion of the liquid when it is heated. Liquid l 6 is heated by a steam pipe [8 extending through lower conduit l5, the said pipe l8 being connected through motorized valve l9 and pipe to the train steam line 2|. The condensate formed in pipe [8 is discharged through a conventional steam trap 22 (Figure 1). To increase the effective radiating area of floor heat means l2, fins 23 may be secured to conduits l4 and I5 in any suitable fashion. For a purpose which will appear, a temperature responsive bulb or device 30 including a thermistor 19 is inserted into conduit I4 or attached to the said conduit, for responding to the temperature of liquid 16. A thermistor is a temperature responsive resistor and comprises. in the present instance, a winding of nickel wire orother material having similar characteristics. The winding of bulb 30, or thermistor 18, forms part of a resistance bridge circuit, to be described.

Although only floor heat means l2 has been described in detail, it is noted that floor heat means [3 is identical with l2 and includes a circulator 24, a steam pipe 25, a motorized valve 26, a steam trap 21, and a thermistor bulb or device 3|. Valve means 26 controls the flow of steam from the train steam line 2| through pipe 28 and pipe in the same manner as previously length of the passenger described. The components of floor heat means (3 are the same as those of floor heat means l2, but have been given different numbers to minimize confusion as the description proceeds.

Motor driven valve means 19, referring to Figure 4, comprises a conventional throttle valve means 34 having a reciprocable stem including a rack 35 adjusted by pinion 36. Pinion 36 is driven through gear train 31 by armature 38 of reversible two-phase motor means 39. Motor means 39 also includes a fixed phase stator winding 40 and an amplifier phase stator winding 41 arranged 90 electrical degrees apart. In addition to adjusting valve 34, rack 35 also adjusts wiper 42 along potentiometer resistor 43.

Motor driven valve means 26 is similar to 19 and includes throttle valve means 44 having a reciprocable stem including a rack 45 adjusted by pinion 46. Pinion 46 is driven through gear train 41 by armature 48 of reversible two-phase motor means 49. Motor means 49 likewise includes a fixed phase stator winding 58 and an amplifier phase stator winding 5| arranged as above described. Rack 45, in addition to adjusting valve 44, also adjusts wiper 52 along potentiometer resistor 53.

Wiper 42 forms one output terminal of a resistance bridge network 55, terminal 56 being the other output terminal of the said network. Network input terminals 51 and 58 are energized by secondary winding 59 of transformer 60. Primary winding 5| of the transformer 60 is energized from line wires 62 and 83 by wires 64 and 65, respectively. The network circuit 55 comprises, reading from output terminal 56 in a clockwise direction: fixed resistor 86, wire 51, input terminal 58, adjustable resistor 68, wire 69, thermistor 10 of device 38, wire 1|, the portion of resistor 43 below wiper 42, output terminal (wiper) 42, the portion of resistor 43 above wiper 42, fixed resistor 12, wire 13, input terminal 51, wire 14, thermistor 15 of wall temperature responsive means 16, wire 11 and output terminal 56.

Wall temperature responsive means 16, shown in section in Figure 3, includes a thermistor 15, having a winding of suitable material such as nickel, held adjacent inner side of the outer skin or wall 18 of car ID by an open side box means 19. Heat insulation 88 is arranged around box 19 to assure that thermistor 15 is aiiected only by the temperature of wall 18. If desired, thermistor 15 may be located on the outer side of wall 18 so that it can respond to the outside air temperature. When located on the outside of wall 18, means to protect the thermistor 15 from sun and wind efiects may or may not be used depending upon the particular installation.

Wiper 52 forms one output terminal for a similar resistance bridge network 85, 86 being the other output terminal of the said network. Input terminals 81 and 88 are energized by secondary winding 89 of transformer 90, primary winding 9| of the transformer 90 being energized from line wires 62 and 63 by wires 92 and 93, respectively. The network circuit 85, reading clockwise from terminal 86, includes: fixed resistor 94, wire 95, input terminal 88, adjustable resistor 98,

wire 91, thermistor 98 of ternperature responsive device 3|, wire 99, the portion of resistor 53 below wiper 52, output terminal (wiper) 52, the portion of resistor 53 above wiper 52, fixed resistor I88, wire llll, input terminal 81, wire l02, thermistor N3 of wall temperature responsive device I94, wire I and output terminal 86. Controller I04 is similar to shown in Figure 3 but obviously is used on the opposite wall of the car.

The output terminal of networks 55 and 85 are sequentially connected in controlling relation to a suitable amplifier I00 by a sequence switch I01, the output terminals of the amplifier being simultaneously connected to the amplifier phase stator windings of motors 39 and 49, respectively, providing manual switch I08 is adjusted for automatic operation, as shown.

Amplifier means I00 is of any conventional sort which maintains a predetermined phase relation between its input signals and its output current. As an example of an amplifier that has the desired characteristics, reference is made to that disclosed in Patent No. 2,423,534 granted to Albert P. Upton on July 8, 1947.

Sequence switch I01 comprises a geared electric motor I98 having a shaft I3I on which are mounted switch blades I09 and H0 for rotation over switch banks III and H2, respectively, the speed of rotation of the blades being preferably about 2 R. P. M.

Manual switch I08 includes blade H4, coacting with contacts H5 and H0; blade II1, coacting with contacts H8 and H9; blade I20, coacting with contacts I2I and I22; blade I23, coacting with contact I24; blade I25, coacting with contact I; and blade I21 coacting with contacts I28 and I29. Blades H4, H1, I20, I23, I and I21 are suitably secured together for simultaneous operation. While this switch is shown as being manually operated, it is contemplated that it may be operated by a pressure responsive device connected to the train's air line, by a thermostatic device, or by other suitable means.

In practice, amplifier I05, sequence switch I01. manual switch I08 and certain of the bridge network components are conveniently located in a suitable control panel and terminal box I30, showrfin Figure 1.

Overhead heating means I I comprises a forced air system including a return air duct I35, a fresh air inlet I for said duct, a motor driven blower I31, a steam heat-exchanger coil I38, a discharge duct I39, and air outlets I40 for distributing the air from said duct I39 into the car. Motor driven blower means I31, although controllable in any desired manner, is preferably controlled from a switch, not shown, operated in conjunction with switch I08. Steam coil I30 receives steam through a motor actuated modulating valve means I4I, similar to valve means I9 and 20, and pipe I42 from the train steam line 2I. The condensate from the coil is discharged through a conventional trap means I43.

Motor driven valve means I4I, similar to valve means I9 and 20, comprises a throttle valve portion I44 (Figure 4) having a reciprocable stem including a rack I45 operated by a pinion I40. Pinion I40 is driven through gear train I41 by armature I48 of motor means I49. Motor means I 49 includes a fixed phase stator winding I50 and an amplifier phase stator winding I5I. In addition to adjusting valve I44, rack I45 also adjusts wiper I52 along resistor I53. Wiper I52 forms an output terminal of a resistance bridge network circuit I of which resistor I53 is a part. The other output terminal of the network I55 is numbered I50. The input terminals I51 and I58 of the network are energized from secondary winding I59 of transformer I00. Primary winding IOI of the said transformer is connected to line wires 02 and 53 by wires I02 and I03, respectively. The network circuit, reading clock- III wise from output terminal I50 includes: wire I04, thermistor I00 of space thermostat I00, wire I01, input terminal I58, wire I08, fixed resistor I09, the portion of resistor I53 to the right of wiper I52, output terminal (wiper) I52, the portion of resistor I53 to the left of wiper I52, fixed resistor I10, wire I1I, input terminal I51, wire I12, fixed resistor I13, and adjustable resistor means I14 back to output terminal I50. Network circuit I55 is connected into controlling relation with amplifier I00 by sequence switch I101 in the same manner as the aforementioned network circuits and the amplifier is likewise connected into controlling relation to motor driven valve means I4I as before. Space thermostat I00 is preferably of the resistance type and includes a thermistor comprising a winding of nickel wire or the like.

In addition to space temperature responsive means I00, a more conventional thermostat I15 including a bimetal I10 and stationary contacts I11 and I18 is provided for controlling the floor heat means to maintain a predetermined relatively low temperature in the car when the manual switch I08 is shifted to its other position for standby operation. Thermostat I15 operates in conjunction with a phase shifting transformer I19 to directly control motor means 39 and 49 without use of amplifier I00. Phase shifting transformer I19 comprises a primary winding I energized by the circuit: line wire 02, wire I8I, wire I82, wire I03, winding I80, wire I84, and wire I back to line wire 03. Secondary winding I80 of transformer I19 includes terminal connections I81 and I88 and a center tap I89.

As before noted, the present apparatus is rather specifically described but it should be kept in mind that this disclosure is intended to be illustrative only and many substitutions and equivalents are readily observed. In the following disclosure of operation, the function of the present apparatus will be set forth and the description thereby made more clear.

Operation With the present apparatus put in operation by the energizing of line wires 02 and 03, it is noted that bridge networks 55, 85 and I55 are energized by circuits previously traced. Likewise, phase shifting transformer I19 is also energized by a circuit just described. In addition. with manual switch I08 in the position shown, it is noted that amplifier I00 is energized by the following circuit: line wire 02, wire I8I, wire I02, wire I90, switch blade I25, contact I20, wire I9I. wire I92, terminal I93 of amplifier I08, terminal I94 of the amplifier, wire I95, wire I90, switch contact I24, switch blade I23, wire I91, and wire I85 back to line wire 03. Motor means I98 of sequence switch I01 is connected in parallel with amplifier I00 by wires I99 and 200.

Fixed phase winding 40 of motor means 39 is energized by the circuit: line wire 02, wire 20I. capacitor 202, winding 40, wire 203 and line wire 03. Likewise, fixed phase winding 50 of motor means 49 is energized by the circuit: line wire 02, wire 204, capacitor 205, winding 50, wire 200 and line wire 03. Fixed phase winding I50 of motor means I49 is energized by the circuit: line wire 02, wire I8I, capacitor 201, winding I50. wire 208 and line wire 03.

With the present control apparatus thus energized, and assuming that there is steam available from the train steam line 2|, and. further assuming that the present railway car is atcircuits, not shown.

An inspection of Figure 4 will show that network circuit 85 is in control of amplifier I06 by the circuit: input terminal 2I0 of amplifier I08, wire 2||,-blade I09 of switch bank III, switch sector 2|2, wire 2I3, wiper 52, network 85, output terminal 86, wire 2|4,-wire 2I5, wire 2I6, and input terminal 2|1 of the said amplifier. Likewise, amplifier I08 is connected to the amplifier phase winding 5| of motor means 49 by the circuit: output terminal2|8 of amplifier I08, wire 2I9, blade of switch bank II2, switch sector 220, wire 22I, switch contact I2I, switch blade I20, wire 222, winding 55, wire 223, wire 224, switch blade II1, contact II8, wire 225 and output terminal 226 of the said amplifier.

Now assume that network 85 has been adjusted by resistor 96 so that a temperature at I04 of 30 requires a temperature at 3| of 130 for balance of the network, and at an outdoor temperature of '10 at I04, a temperature of 80 is required at 3| for balance. Thus, there should be a 1 change in water temperature for each 2" change outside to keep the network in balance. this generally being arranged by using twice as much wire in thermistor 98 of device 3| as is used in thermistor I03 of controller I04. Then, assuming that the outdoor temperature is +40, the liquid temperature in floor heat means I3 to which device 3| responds should be 95. With this temperature at 3| and under the conditions stated, network 85 is balanced and has no output current, therefore there is no signal to the amplifier. From this it follows that there is no effective output current from the said amplifier, hence winding of motor means 49 is not operatively energized and motor means 49 does not operate.

However, further inspection of Figure 4 will indicate that throttle valve 44 is approximately half open and steam is being supplied to floor heat means I3 to increase the temperature of the same. With the temperature of floor heat means I3 rising, assume that it now rises above 95". A rise in temperature at 3| resulting in increased resistance of thermistor 98, unbalances the network and results in a signal being imposed on amplifier I06 by the circuit previously traced. As this network is energized by alternating current, and an unbalance of a network so energized results in a signal of one phase or another depending upon which way the network is unbalanced, it now appears that the present unbalance will result in a signal of a phase which will cause amplifier I08 to energize amplifier winding 6| in a manner to drive armature 48 in a direction to move rack 45 and wiper 52 downwardly to restore the balance of the -net work. It is obvious that this is the correct direction of movement, for an increased resistance at 38 requires a lowered resistance on the bottom portion of resistor 53 and an increased resistance on the upper portion of resistance 53 to rebalance the network. However, it will be noted that downward movement of rack 45 results in a throttling of valve 44 and thus results in a lower delivery of steam to floor heat means I3. This is the correction that is desired because the rising temperature oi. floor heat means I3 can be corrected only by decreasing the amount of steam supplied to the said floor heat means. With sequence switch I01 rotating at 2 R. P. M., it is noted that ,switch blade I09 will remain on sector 2I2 for approximately ten seconds. If the desired correction can be made in ten seconds, for instance., ,va1ve 44 will be properly positioned and the network rebalanced in that time. However, if the correction is not completed within that time the correction will be continued at the next revolution of the said switch.

While it is obvious that an increase in resistance at 98 due to an increase in temperature at 3| unbalances the network in a manner to cause closure of valve 44, it is equally obvious that a temperature too low at 3|, causing a low resistance of 98 will unbalance the network in an opposite direction and thereby require an opposite movement of rack 45 and wiper 52 to rebalance the network. This, of course, results in more steam being added to raise the temperature of the fioor heat means. It also follows that a decrease in resistance of I03 will unbalance the network in the same manner, although to a lesser extent, .as an increase in temperature and resistance of 98. Thus, if the outside tempera ture should drop to 10, for instance, the resistance of I03 becomes low, a signal is imposed on amplifier I06, due to the unbalance of the network, which will be of the same phase as that caused by a low resistance of 98, thereby causing operation of motor means 49 in a direction to open valve 44 and increase the temperature of 98. In other words, it can be assumed that thermistor 98 is a controlling resistor for the network and thermistor I03 establishes a control point for the network depending upon outdoor temperature.

Assuming that sequence switch I01 is rotating clockwise, when blades I09 and 0 move from sectors 2I2 and 220 to the next clockwise sectors, network I55 is placed in charge of amplifier I06 by the circuit: input terminal 2I0 of the said amplifier, wire 2| I, switch blade I09, switch sector 231, wire 228, wiper and output terminal I52, network I55, output terminal I56, wire 229, wire 2I6 and input terminal 2I1 of the said amplifier. Likewise, the amplifier I06 is placed in charge of amplifier winding I5I of motor means I49 by the circuit: output terminal 2 I8 of the said amplifier, wire 2I9, blade 0, switch sector 230, wire 23I, contact I28, switch blade I21, wire 232, winding I5I, wire 233, wire 224, switch blade II'I, switch contact II8, wire 225, and amplifier terminal 226. With the overhead heating system now being controlled, it is noted that valve I44 is partly open, heat is being supplied to the air being delivered through duct I39 and outlets I40 and, if device I66 is at the temperature desired, network I55 will be balanced. However, if the temperature at I66 should be lower than that desired, or if a new and higher control point should be selected by adjusting resistor I14, then the network I55 becomes unbalanced due to the relatively low resistance in the upper right-hand branch of the same. This causes a signal to be impressed on amplifier I06 by the circuit previously traced and of a phase causing the output current from the amplifier to operate motor means I49 in a direction to drive rack I45 and wiper I52 to the right. Moving wiper I52 to the right across resistor I53 acts to restore the balance of the network and causes further opening of the valve I44 resulting in the delivery of more heat to the space as called for by the low temperature at device I88. From this it follows that a higher resistance of I65, due to a relatively high temperature affecting device I66, will cause the network I55 to become unbalanced in an opposite direction, a signal of opposite phase will be imposed on amplifier I06 and the output current of amplifier I06 of an opposite phase will cause operation of motor means I49 in a reverse direction. This will cause movement of rack I45 and wiper I52 to the left and result in a closing of valve I44 and a limiting of the heat supplied by the overhead heating means.

A further rotation of sequence switch I01 in a clockwise direction places network 56 in control of amplifier 56 by the circuit: input terminal 2I0 of amplifier I06, wire 2I I, switch blade I09, switch sector 235, wire 23G, wiper (output terminal) 42, network 55, output terminal 56, wire 231, wire 2I5, wire 2I6, and input terminal 2" of the amplifier I06. In addition, the amplifier is in control of winding H of motor means 39 by the circuit: output terminal 2I8, wire 2I9, switch blade IIO, switch sector 238, wire 239, contact II5, switch blade II4, wire 240, winding 4I, wire 24I, wire 224, switch blade II1, contact II8, wire 225, and output terminal 226 of amplifier I06. Assuming that network 55 is adjusted similarly to network 85, and that the same temperatures are required at devices 16 and 30 for balance of this network as were required at devices I04 and 3I of network 85, it will now be noted that valve means 34 is substantially closed. This indicates either a high temperature at device 30 or a high temperature at device 16.

Assuming that the network 55 became balanced in the position shown due to a high temperature at 16 which was due to the near side of the car being exposed to sunshine and thereby warming the wall above the temperature of the opposite wall, then it follows that when the sun is obseured for some time and the wall temperature affecting device 16 decreases, the said network will become unbalanced and impose a signal on amplifier I08by a circuit previously traced of a sort to cause rotation of motor means 39 in a direction to open valve 34 and increase the temperature of floor heat means I2. Thus, before the cooling of wall 18 can have an effect on the passengers seated inside the car and along that side, the operating temperature of floor heat means I2 is increased to offset the drop in temperature of the wall and thereby maintain a uniform resultant temperature of the inner wall of the car. It is thus obvious that changes in temperature at device 30 affecting the resistance of thermistor 10 will cause signals to be imposed on amplifier I which will result in operation of valve means I9 to increase or decrease the temperature of floor heat means I2 as required and as determined by the temperature detected by device 16.

Because of the relatively low temperatures maintained by floor heat means I2 and I3, the total amount of heat they add to the car is only a minor portion of the total amount needed, most of the heat being furnished by the overhead system. However, due to the floor heat means being modulated to keep the wall and floor area comfortably warm, persons sitting adjacent the wall, as well as those next to the aisle, will be comfortable with a predetermined air temperature in the car. Further, as this comfortable feeling due to the warmed walls is maintained 10 regardless of variations in outside temperature, a uniform space temperature may be maintained under all normal heating conditions. This makes for ease of control and satisfaction to the passengers. Further, since each floor heat means is controlled by its individual network,'variations in sun effects, wind effects, train speed and the like are compensated in the same manner as variations in temperature, due to sun tending to add to the temperature of the side wall and the wind or speed tending to lower the temperature of a side wall.

When the railway car is placed in standby operation and heating is necessary only to prevent freezing of the liquids in the car and also to permit it to be warmed to operating temperature without too much delay, manual switch I08 is operated to its other set of contacts. As before noted, instead of manually operating this switch it can be operated by connecting to the train air line so that it assumes this other position whenever the pressure is decreased in the train air line, as when the train is on a siding. When the switch I08 is shifted to its other position, as noted, it will be seen that the circuits energizing sequence switch I01 and amplifier I08, through switch blades I23 and I25, are opened due to the disengagement of the said switch blades with their contacts. At the same time, thermostat I15 is placed in control of floor heat means I2 and I3 and motor driven valve means I is driven closed. Tracing the circuits, it is noted that the amplifier phase winding I5I of motor means I49 is now energized from phase shifting transformer I19 by the circuit: terminal I81 of secondary winding I86, wire 245, wire 246, contact I29, switch blade I21, wire 232, winding I5I, wire 233, wire 224, switch blade I I1, contact II9, wire 241, and center tap I89 of the said transformer secondary winding. When energized in this manner, motor means I49 is driven in a direction to close valve I44 and thereby stop the overhead heat.

It was previously noted that the circulators of the floor heat means and blower means I31 were preferably controlled in conjunction with manual switch I08 hence it may be assumed that they have been deenergized and are not now operating. However, the supply of heat to the floor heat means can be controlled by circuits, starting with the center tap I89 of transformer winding I86, as follows: tap I89, wire 241, contact II9, switch blade II1, wire 224, wire 223,

winding 5|, wire 222, switch blade I20, contact I22, wire 248, wire 250, bimetal I16, and either contact I11 or contact I 18. Contact I11 is connected to terminal I88 of transformer secondary I86 by the wire 25I and contact I18 isconnected to terminal I81 of the secondary winding by wires 252 and 245. Assuming that the temperature atfecting bimetal I16 is above the predetermined control point, such as the bimetal portion would be operated against contact I18 completing the circuit through wires 252 and 245 to terminal I89 of transformer I19, thereby energizing motor means 49 by the same portion of the transformer which drove motor means I49 in a closed direction. This would likewise result in driving motor means 49 in a direction to close valve 44 and thus diminish the heat at floor heat means I3.

Floor heat means I2 is controlled in the same manner by the circuit: center tap I89, wire 241, contact II9, switch blade II1, wire 224, wire 24I, winding 4I, wire 240, switch blade II4, contact 11 H3, wire 233, wire 258, bimetal I16, contact I18, wire 232, wire 245 and terminal I81 of secondary winding I86. Since the current furnished winding 4| of motor means 39 is of the same phase as that furnished winding SI of motor means 49, it is obvious that motor means 39 will also be driven in a valve closing direction due to the excessive temperature affecting b etal I16.

However, should the temperatur at I16 drop below the aforementioned 60, the above circuits are completed from bimetal I18 through contact I11 and wire 25I to terminal I88 of phase shifting transformer I19. Due to the characteristics of transformers of this sort, it will be noted that the output current is now of reverse phase to that previously supplied to motor windings H and 5!, hence motor means 39 and 49 will be driven in a valve opening direction to supply more heat. Since there is no means to limit the temperature that can be attained by floor heat means. I2 and I3 when controlled from thermostat I15, the said floor heat means will tend to operate at their maximum temperature until the heat demands of the car are satisfied. Obviously, when switch I88 is shifted to the position shown, thereby placing the system under normal control again, the high temperatures existing in floor heat means I2 and I3 will cause unbalance of the respective networks sufllciently to prevent any further addition of heat until the said fioor heat means have cooled to the desired temperature.

It will thus be noted that in addition to properly controlling the temperature of the car under normal conditions, the present system is readily adapted to standby control operation with a minimum of apparatus being used for such operation.

While the present system has been disclosed as particularly useful for railway cars, it may also be used in homes, as will be more specifically disclosed in the following modification which is shown in Figure 5 of the drawing.

Figure 5 3I8 supplies heated air to a plenum 3 from which a riser duct 3I2 delivers air to space 3I3. The fiow of heated air through duct 3I2 is controlled by a damper means 3" which is adjusted by a proportioning motor means 3I5 acting through a' suitable linkage- Proportioning motor means 3I5 is controlled by a suitable proportioning room thermostat 3I6. Motor means 3I5 and controller 3I6 are well known in the art and are fully described in Taylor Patent No. 2,028,110. Return air from the room is taken by duct 3I1 to main return air duct 3I8 and forced by motor driven blower 3I9 into furnace 3I8.

In addition to heating the air delivered to the said furnace, furnace 3) also includes a pipe coil 328 for heating water in a storage tank 32I, said coil 328 being connected to tank 32I by an upper pipe 322 and a lower pipe 323. Baseboard radiators 324 and 325, located along the outer walls of space 3 I 3, are supplied with heated water from tank 32l through supply pipe 326, threeway valve means 321, supply pipe 328, and pipes 328 and 338, respectively. The water is returned from radiators 324 and 325 through pipes 332, 333. 334, return riser 335, circulator 336 and pipe 331. A by-pass pipe 338 is connected between return pipe 331 and three-way valve 321.

By operation of three-way valve 321, the temperature of the water delivered to radiator 324 and 325 can be varied from that of the return water to the temperature of the water in tank 32I and depends upon the position of member 339 of the said three-way valve. In the position shown, all of the water supplied to the radiators is furnished through by-pass 338 and none is furnished from tank 32I, the water supplied thus being at return water temperature. Valve member 339 is adjusted by a proportioning motor 348, similar to motor 3I5 and therefore similar to that described in the aforementioned Taylor patent. Control is exercised over motor 348 by device 34I which includes a bulb 342 responding to the temperature of the water supplied to radiators 324 and 325 and bulb 343 responding to outdoor temperature, bulbs 342 and 343 being connected to bellows 344 by suitable capillary tubes. Bellows 344 operates potentiometer wiper 345 across resistor 343' to control motor means 348 in the manner described in the aforementioned patent.

Furnace 3| 8 may be heated in any conventional manner such as by an oil burner 341 controlled by device 348. Device 348 includes a bonnet temperature responsive bulb 349 and an 4 outdoor temperature responsive bulb 358 connected by suitable capillary tubes to bellows 35L Bellows 35I operates mercury switch means 352 in a manner to close the switch contacts 353 and 354 when the joint pressure caused b bulbs 349 and 358 is relatively low and to open the contacts when the said pressure is relatively high. In effect, device 348 attempts to maintain a prede termined bonnet temperature for each outdoor temperature with the bonnet temperature being varied upwardly as the outdoor temperature varies downwardly. Device 348 is preferably adjusted to cause the air for space 3I3 to be heated to a somewhat higher temperature than is needed to'meet the demands of the said space. The ultimate control of the heat added to the said 0 space is then effected by damper 3 which limits the volume of air delivered to the space in response to the temperature at thermostat 3I6.

In this modification, as in the previous example, base-board radiators 324 and 325, analogods to floor heat means I2 and I 3 in the previous example, are heated only sufliciently to maintain the mean radiant temperature within the space substantially constant. In this modification. as before, the temperature of the radiator is adjusted upwardly by device 3 as the outdoor temperature falls but at no time are radiators 324 and 325 operated at a sufilciently high temperature to carry more than a lesser portion of the heat load of the space 3| 3. In this manner, there is no overshooting of temperature due to the floor heat means and efiective control can be maintained by thermostat 3 I 6.

Operation of Figure 5 motor 358 of blower 3| 9 is energized by the circuit: line wire 380, wire 384, wire 355, motor 356, wire 351, wire 358 and line wire 38L The circuit for oil burner 349 is: line wire 380, wire 3B4. wire 359, wire 360, oil burner 341, wire 36l, switch contact 354, contact 353, wire 362, wire 363, wire 358 and line wire 38L Motor means 340 and 3l5 are energized through a transformer 365 wherein primary winding 366 is energized by the circuit: line wire 380, wire 384, wire 359, wire 361, winding 366, wire 368, Wire 363, wire 358 and line wire 38l. Secondary windin 369 is connected to motor means 340 by wires 310 and 31! and to motor means 3l5 by wires 312 and 313.

With the apparatus energized as above described, it is noted that circulator 336 is operating, blower means 319 is operating, oil burner 341 is not operating, valve means 339 is in a position to by-pass all liquid, and damper means 3 is in a position to restrict the flow of air through duct 3l2.

Assuming that device 348 will maintain a bonnet temperature of 200 at a design temperature of -35", and will maintain a bonnet temperature of 100 at an outdoor temperature of 65", it will be noted that the bonnet temperature is increased 1 for each degree decrease in outdoor temperature. Baseboard radiator means 324 and 325 may be maintained at a temperature, or rather the water supplied to them may be at a temperature varying from 80 to 130 as the outdoor temperature varies from 65 to a -35, or for each degree change downwardly in outdoor temperature, the liquid temperature is raised To accomplish this, the capacity of bulb 342 is made twice that of bulb 343. Assumin that the outdoor temperature is above zero, then it appears that a bonnet temperature of 150 is called for, and a base-board temperature of 105 is required. The area of base-board radiators 324 and 325 is such, and the temperature at which they operate is so adjusted that sufllcient heat is added by them to maintain the walls, especially the lower portion of the walls, and the floor at such temperatures that the mean radiant temperature in the space 3l3 remains substantially constant under varying conditions.

With valve member 339 at its extreme by-pass position, it appears that either the liquid temperature at bulb 342 or the outdoor temperature at bulb 343 is relatively high and the pressure in bellows 344 has resulted in wiper 345 being driven to the bottom of resistor 346 thus causing motor means 340 to drive the said valve member to the position shown. In this position, as before noted, all of the water circulated through the system flows through by-pass 338 and none of it goes through tank 32!, hence no heat is being added to radiators 324 and 325 from tank 32 I. In addition, it is noted that either the bonnet temperature at bulb 349 is over the above mentioned 150, or the outdoor temperature at bulb 350 is over 15, or both, and therefore the pressure in bellows 35l is relatively high and contacts 353 and 354 are open. The space temperature is apparently near its control point for thermostat 3l6 is shown at an intermediate point on resistor 314 and damper means 3 is accordingly adjusted to an intermediate value.

Assuming that the outdoor temperature now drops several degrees, the pressure generated by bulb 350 will be decreased, the pressure on bellows 35! will be decreased and switch means 352 will be tilted in a direction to close contacts 353 and 364. This will cause oil burner 34! to be energized by the aforementioned circuit and operate to increase the bonnet temperature. When the bonnet temperature rises to a new and higher value, the added pressure generated by bulb 349 will again cause opening of switch 352 in an obvious manner. The decrease in outdoor temperature will also cause a reduction in pressure at bulb 343 and thereby cause a retraction of bellows 344. This will move wiper 345 upwardly across resistor 346 and cause motor means 340 to move valve member 333 in a direction to restrict the flow of liquid through by-pass 333 and increase the flow through tank MI and supply pipe 328. This will tend to increase the temperature of liquid flowing through pipe 328 to baseboard radiators 324 and 325 and will cause an increase in pressure at 342 to counteract the decrease in pressure at bulb 343. When the increase in pressure exerted by bulb 342, due to the increased water temperature, is sufllcient to offset the decrease in pressure due the lower temperature at bulb 343 so that further movement of bellows 344 is prevented, motor means 340 will be stabilized and valve member 333 will remain in the adjusted position until a further change takes place.

In the event of a temperature rise outdoors, the opposite controllingaction takes place. The increase in temperature at bulb 350 causes switch means 352 to remain in a contact open position and thereby prevent further operation of burner means 341 until the bonnet temperature drops sufliciently that the pressure generated by bulb 349 is decreased an amount sufficient to ofiset the increase in pressure at bulb 350 before the switch means can again be closed. Similarly, an increase in pressure at bulb 343 due to a rising outdoor temperature tends to increase the pressure in bellows 344 thus driving wiper 345 to the position shown wherein valve member 339 is adjusted to a by-pass position so that the liquid temperature at bulb 342 will gradually drop due to heat loss through radiator 324 and 325 and no heat being added from tank 32!, until the rise in temperature at 343 is offset by the deer-ease in temperature at 342.

From the above disclosure, it is seen that the present invention may comprise a steam, forced air, or hot water heating system and is of a sort readily adapted for use in old structures as well as new. In addition, by providing sufficient heat near the walls and floor to maintain the mean radiant temperature substantially constant, comfort can be achieved by maintaining a relatively constant air temperature in the space. This results in a more satisfactory heating system from the standpoint of the occupants and, for the results accomplished, a simplified control system.

The present disclosure is intended to be illustrative only and subject to many substitutions and equivalents hence the scope of the present invention is to be determined only by the appended claims.

We claim as our invention:

1. In a railway car, in combination, individual floor heat means arranged along each side and near the floor of the car, each of said floor heat means comprising a closed loop containing a suitable heat exchange liquid, means for circulating the liquid in each of said loops, individual steam heating means for heating the liquid in each of said loops, valve means for controlling each of said steam heating means, individual means for controlling each of said valve means,

each of said individual means including means responsive to the liquid temperature of a floor heat means and means responsive to the outer wall temperature on the respective side of the car, each of the said individual controlling means operating to maintain a predetermined liquid temperature for each outer wall temperature with higher liquid temperatures being required as the outer wall temperatures decrease, means responsive to car temperature for also controlling said valve means when the said car is in standby service, overhead heating means including circulating means for supplying heated air to said car, and means responsive to car air temperature for controlling the said overhead heating system, the said overhead heating system being designed and arranged to provide the major portion of the heat demands of the car and the floor heat system being designed and controlled to furnish a lesser fraction of the total heat needed by the said car.

2. In a railway car heating system, overhead heating means for supplying the major portion of the heat demand of the said car, means responsive to car temperature for controlling said heating means. floor heat means along each side of said car, means for changing the temperature of each of said floor heat means, and means for proportionally controlling said temperature changing means comprising apparatus jointly responsive to the temperature of each of said floor heat means and to the outer wall temperature on each side of the car so that the temperature of each of the said floor heat means may be varied inversely as the temperature of the respective outer wall varies.

3. In apparatus for heating a space, heating plant means for heating both a liquid and air, means for circulating the heated air to said space, means responsive to space temperature for controlling the circulating of said air, means responsive to the temperature of the air circulating through the said heating plant and means responsive to outdoor temperature for jointly controlling said heatin plant, floor heat means along substantially the full length of at least one of the walls of said space, a liquid storage tank, means connecting said tank to the liquid heating means of said heating plant, means circulating a liquid through said tank and said floor heat means, a by-pass connection around said tank, mixing valve means for controlling the relative flows through said by-pass means and the said tank and thereby controlling the temperature of the liquid supplied to said floor heat means, means responsive to the temperature of the liquid in said floor heat means, and additional means responsive to outdoor temperature, the said floor heat temperature responsive means and said additional temperature responsive means coacting to jointly and proportionally control said mixing valve.

4. In heating apparatus for an enclosed space, in combination, air heating means for said space,

16 means responsive to space temperature for controlling said air heating means, radiant heat means for radiating heat within said space, said radiating means comprising a closed loop conduit containing a liquid, means for heating the said liquid, means for circulating the liquid, and means for controlling the liquid heating means including means responsive to the liquid temperature and to outdoor temperature arranged to vary the liquid temperature inversely proportional to outdoor temperature.

5. In heating apparatus for a space, in combination, a closed loop conduit means for containing a liquid, said conduit means including elongated horizontal portions relatively close together, means for heating the liquid within said conduit, means for circulating the said liquid, means for conrolling said liquid heating means, and means for regulatingsaid controlling means including means responsive to the liquid temperature and to a temperature indicative of outdoor temperature arranged to vary the liquid temperature inversely proportional to the outdoor temperature.

6. In heating apparatus for an enclosed space having an outside wa1l,'in combination, air heating means for said space, means responsive to space temperature for controlling said air heating means, radiant heat means for radiating heat within said space, said radiating means comprising liquid conduit means extending along substantially the full length of said outside wall and being part of a closed liquid circulating system, means for heating the liquid in said circulating system, means for circulating the liquid, and

means for controlling the liquid heating means including means responsive to the liquid temperature and to outdoor temperature arranged to vary the liquid temperature inversely proportional to outdoor temperature.

VERNON D. WISSMILLER. ROBERT A. BEVERIDGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 306,707 Wheat et al. Oct. 14, 1884 2,065,481 Thulman Dec. 22, 1936 2,182,449 Parks et al. Dec. 5, 1939 2,257,471 McGrath Sept. 30, 1941 2,282,441 Whitlock May 12, 1942 2,282,442 Whitlock May 12, 1942 2,307,723 Anderson Jan. 5, 1943 2,319,315 Garvey May 18, 1943 2,346,592 Lehane et al. Apr. 11, 1944 2,404,596 Roche July 23, 1946 2,404,597 McClain July 23, 1946 2,431,790 Crosthwait Dec. 2, 1947 2.451566 Lehane et al. Oct. 19, 1948 

